fixup uptime in stats

startup_time was changed to monotonic without properly changing all the
places it was used.
change startup_time back and add startup_time_mono

readsb.c

@@ -2689,7 +2689,8 @@ int main(int argc, char **argv) {
     // Set sane defaults
     configSetDefaults();
 
-    Modes.startup_time = mono_milli_seconds();
+    Modes.startup_time_mono = mono_milli_seconds();
+    Modes.startup_time = mstime();
 
     if (lzo_init() != LZO_E_OK)
     {

readsb.h

@@ -855,6 +855,7 @@ struct _Modes
     ALIGNED struct mag_buf mag_buffers[MODES_MAG_BUFFERS]; // Converted magnitude buffers from RTL or file input
 
     int64_t startup_time;
+    int64_t startup_time_mono;
     int64_t next_stats_update;
     int64_t next_stats_display;
     int64_t next_api_update;

stats.c

@@ -660,12 +660,8 @@ struct char_buffer generateStatusProm(int64_t now) {
 
     struct statsCount *sC = &(Modes.globalStatsCount);
 
-    int64_t uptime = now - Modes.startup_time;
-    if (now < Modes.startup_time)
-        uptime = 0;
-
     p = safe_snprintf(p, end, "readsb_now %"PRIu64"\n", now);
-    p = safe_snprintf(p, end, "readsb_uptime %"PRIu64"\n", uptime);
+    p = safe_snprintf(p, end, "readsb_uptime %"PRIu64"\n", getUptime());
 
     p = safe_snprintf(p, end, "readsb_aircraft_with_position %u\n", sC->readsb_aircraft_with_position);
     p = safe_snprintf(p, end, "readsb_aircraft_without_position %u\n", sC->readsb_aircraft_total - sC->readsb_aircraft_with_position);
@@ -686,11 +682,7 @@ struct char_buffer generateStatusJson(int64_t now) {
     size_t buflen = 8192;
     char *buf = (char *) cmalloc(buflen), *p = buf, *end = buf + buflen;
 
-    int64_t uptime = now - Modes.startup_time;
-    if (now < Modes.startup_time)
-        uptime = 0;
-
-    p = safe_snprintf(p, end, "{ \"now\": %.1f, \"uptime\": %.1f", now / 1000.0, uptime / 1000.0);
+    p = safe_snprintf(p, end, "{ \"now\": %.1f, \"uptime\": %.1f", now / 1000.0, getUptime() / 1000.0);
 
     p = appendTypeCounts(p, end);
 
@@ -903,10 +895,7 @@ struct char_buffer generatePromFile(int64_t now) {
         p = safe_snprintf(p, end, "readsb_trace_chunk_memory %"PRIu64"\n", Modes.trace_chunk_size);
         p = safe_snprintf(p, end, "readsb_trace_cache_memory %"PRIu64"\n", Modes.trace_cache_size);
     }
-    int64_t uptime = now - Modes.startup_time;
-    if (now < Modes.startup_time)
-        uptime = 0;
-    p = safe_snprintf(p, end, "readsb_uptime %"PRIu64"\n", uptime);
+    p = safe_snprintf(p, end, "readsb_uptime %"PRIu64"\n", getUptime());
 
     if (p >= end)
         fprintf(stderr, "buffer overrun stats prom\n");

util.c

@@ -118,7 +118,7 @@ int64_t mono_milli_seconds() {
 }
 
 int64_t getUptime() {
-    return mono_milli_seconds() - Modes.startup_time;
+    return mono_milli_seconds() - Modes.startup_time_mono;
 }
 
 int snprintHMS(char *buf, size_t bufsize, int64_t now) {